and we search for the optimal staffing to complete the project within 26 weeks – by applying Formula 2:

Average WIP =0.967526=23.36

This means you’ll need 24/2 (average WIP of every team member) = 12 team members to accomplish the project within 26 weeks.

And what happens if you have to finish it in 18 weeks?

Average WIP =0.967518=33.75

This means you’ll need 34/2 = 17 team members to accomplish the project within 18 weeks.

Now let’s fix the number of people to 12 (2 teams with 6 team members each) and we need to forecast the project duration.

Duration =number of storiesaverage lead timeaverage WIP

Duration =6750.924(12 people x 2 items each)=25.3weeks

What a nice extension for release planning.

In addition we need to consider that work delivery rates in projects are not uniform but tend to follow a fairly predictable S-Curve (with delays in the beginning and at the end of a project).

Little’s Law can therefore be applied with high confidence to only the middle portion of most projects (approximately 60% of total project duration).

For the remaining 40% of the project we need to work with a project buffer that can be calculated using the formula I’ll describe in my next post (just subscribe to receive your weekly updates right in your inbox ;-).